No, vehicles from the 80s and some earlier have been designed to run on it. People in the North put Heet in their tanks, they are putting alcohol in their tanks. The article you linked is pretty much analogous to saying, if you cover yourself in gas and smoke you will probably hurt yourself. If you mix Jello in your fuel it will probably have undesirable effects. That is the quality of the reporting.
Now it will be less fuel efficient but it is a percentage of a percentage so it isn't going to be terribly huge. They went to ethanol because they were getting MTBE in the water supply which was the chemical that was used before ethanol. Now I won't debate if that was from leaking fuel tanks or from liquefied emissions from vehicles. Just saying why they want to it. It wasn't to replace 10% of the fuel, it was to add an oxegenator to the fuel. Now going over 10% that is a different story and we can start a thread in an off topic area talking about conversion rates of different biomass.